Protective system for a diaphragm pump



April 6, 1965 H. K. HOWERTON ETAL 3,176,623

PROTECTIVE SYSTEM FOR A DIAPHRAGM PUMP Filed July 20, 1962 m T m u m a Bm m 5 0 a T W 6 MM F WZ% 3 u w v1 0 3 W AX J 3 H5 N 4 MN m M 2 .U H mm Mw 7 if 1% F w/ A F'IEZ 0.: our

United States Patent 3,176,623 PRGTEQTWE SYJEEM FGR A DEAPHRAGRE PUMPHugh l5. Howerton, Silver Spring, and Allen E. Eladeu,

This invention relates to compressors and pumps of the diaphragm type,and more particularly to a warning and protective system for a pump orcompressor of the type employing an oscillating diaphragm driven by anoperating fluid as the means for compressing or pumping a gas.

A main object of the invention is to provide a novel and improvedwarning and protective system for use with a diaphragm pump, the systembeing arranged to detect leakage of operating fluid associated with thepump and to provide a positive warning of such leakage as well as todeenergize the pump and cut of? the of gas thereto, whereby to preventthe contamination of gas undergoing compression.

A further object of the invention is to provide an improved protectivesystem for a diaphragm pump which is automatically operated to stop thepump and cut off the supply of gas thereto when any leakage of operatingfluid occurs therein, whereby to prevent contamination of gas undergoingcompression, the system involving relatively simple parts, being highlysensitive, and providing a quantitative visual indication of thepresence and amount of such leakage as well as an automatic alarm whenthere is leakage.

A still further object of the invention is to provide an improvedautomatic operating fluid leakage detecting and alarm system, as well asan automatic supply valve controlling system for a diaphragm pump, saidsystem involving relatively inexpensive components, being reliable inoperation, and greatly amplifying the usefulness of such pumps.

Further objects and advantages of the invention will become apparentfrom the following description and claims and from the accompanyingdrawings, wherein:

FIGURE 1 is a diagram showing the schematic piping and electricalconnections of an improved diaphragm pump protective system constructedinaccordance with the present invention.

FIGURE 2 is a perspective view of the leak detector employed in thesystem of FIGURE 1.

FIGURE 3 is a diagram showing a plan view of the optical arrangementemployed in the leak detector of the protective system of FIGURE 1.

Referring to the drawings, 11 generally designates a diaphragm pump ofgenerally conventional construction, said pump comprising a pair ofplates 12 and 13 defining between them a biconical compression chamber14. The plate member 12 is provided'with suitable gas intake anddelivery valves (not shown) provided in ports communicating with the gassupply and delivery conduits shown respectively at 15 and 16, while theplate 13 is formed with perforations or ports 17 through which anoperating fluid, such as oil or water, is alternately discharged andsucked, by a piston, not shown, acting in the pump body 18. Mountedacross the chamber 14 is a composite diaanaszs Patented Apr. 6, 1965 ahousing 32 having the inlet conduit 33. and the outlet conduit 34opposite inlet conduit 33, as shown, thehousing being generallyrectangular, for example. The inlet conduit 33 may be connected to thecentral portion. of one side wall 2%) of the housing and the outletconduit 34 may be connected to the opposite side wall 21 thereof at apoint ofiset forwardly relative to the inlet conduit 33, as shown inFIGURE 3.

A suitable source of exciting radiation, such as an ultraviolet orvisible light source 36, is mounted to emit radiation into the housingthrough an admission tube 37 connected to the intermediate portion ofthe front wall 38 of the housing substantially perpendicular to the pathof gas flowing through the housing. Tube 37 is provided with a window 43transparent to the radiation from source as and with an optical filter23 to pass only a'desired wavelength or narrow Wavelength range of theradiation 7 from said source.

phragm assembly 19 consisting of several thin diaphragm elementsarranged one upon the other, clamped together at their periphery betweenthe plates 12 and 13, and movable in vibratory reciprocation as a singleunit under the action of the operating fluid within the compression chamber 14, thus causing correlated suction and discharge of the gas on theface of the diaphragm assembly opposite from that subjected to theaction of the driving fluid.

Designated at 27 is a detector device, which comprises Mounted obliquelyin the housing 32 in a position to receive radiation from the source 36and also to receive the gas flow from the inlet conduit 33 is a platemember 24 which is coated with non-reflective material, for example,lustreless black lacquer such as Lustreless Black Lacquer No. E27,manufactured by Lenmars Lacquers, Inc, Baltimore, Maryland. The platemember 24- may be mounted at approximately an angle of 45 to the axis oftube 37 and to the axis of conduit 33, in the path of the incoming gasfrom conduit 33, as shown in FIGURE-3.

A detector tube 4% is connected to the corner portion of housing 21between the front wall 38 and side wall 253, said tube extending in adirection normal to the plate member 2.4, namely, at an angle of 45 tothewalls 38 and 29. A photosensitive device 43, such as a photocell or aphotomultiplier tube, is mounted to receive radiation excited inmaterial collected on plate member 24 as a result of impinging directradiation thereon from the source 36. I

As shown in FIGURE 1, the gas inlet and outlet conduits 33 and 34 areconnected to spaced points along the pump outlet conduit 1d so as tocirculate a sample of the gas discharged from the pump through the leakdetector 27.

A suitable fluorescent tracer material may be provided in the operatingfluid, such as Fluorescein or 4 -Methylumbelliferone, or it is possibleto utilizethe natural luminescence of commercial oils. Such fluorescentindicating material, if used, maybe dispersed in a medium which issoluble in the operating fluid, so thatin theevent of leakage of saidoperating fluid into the detecting housing 32, the indicating material,depositing on the plate member 24, will fluoresce when excited byaradiation from source 36, andsuch fluorescence will activate thephotosensitive device 43 and generate an electrical signal. The

output of device 43 is amplified in a suitable amplifier 44 and isapplied to an indicating meter 45 of the relay type.

The meter 45 is provided with a conductive indicating arm 46 which isengageable with a stationary contact 47 at a signal valve correspondingto the appearance of leakage, or to a maximum limit ofleakage,.whichever is desirable. I 7

As shown diagrammatically in FIGURE 3, the housing 32 is provided withthe suitable low-fluorescence windows transparent to ultraviolet light,shown at 48 and 419, such as silica windows, for transmitting theradiation from the source 36 to the interior of the housing and from thefluorescing indicating material to the. photosensitive device 4-3. a c

An optical cut-oil filter 26 is provided in tube 40 to prevent theexciting radiation from source 36 from reaching the photo-sensitivedevice 43 but permitting luminescence of hydrocarbons depositing onplate member 24 to source 51. A wire 53 is connected to the stationarycontact 47. One terminal of the alarm device 50 is connected to wire 53and the other terminal thereof is connected to a wire'54,"which isconnected in turn to the remaining terminal of source 51.

Wires 53 and 54 are connected to the winding of a relay 55 having afirstarmature 56 which normally engages a 1 contact 57. A solenoid valve58 is provided in the gas supply" conduit 15. The winding of valve 58 isconnected to a pair of current supply wires 59 and 60 through armature56 and contact 57. Valve 58 is open when energized and closed whendeenergized. Therefore, when 61 and contact 62, asshown, so'that saidmotor becomes deenergized responsive to the energization of relay 55.

The alarm device 50 becomes energized simultaneously with theenergization of relay 55, providing the warning signal indicating thatthere is leakage of the operating fluid.

If desired, valve 58 and its control circuit may be omitted, but thebasic operation of the indicator will remain unchanged.

The meter 45 provides a continuous indication showing the amount ofleakage so that it is possible to ascertain at all times whether or notthe pump is in a safe condition and to detect the failure ordeterioration of the dia- "Phragm element 21.

If desired, the meter scale may be eliminated and the device may be usedsimply to cut off the pump or to provide an alarm at a predeterminedleakage point.

In a typical detection device according to the present invention, theexcitation radiation from source 36 monochromated by and passing throughthe filter 23 had a wavelength of 3280 Angstrom units; the emissionradiation (from the leakage material deposited on plate member 24)passing through the filter 26 had a wavelength of 4100 Angstrom units;the filter 26 was designed to block all radiation .having a wavelengthbelow 3500 Angstrom units;

While a specific embodiment of an improved protective system for adiaphragm pump or compressor has been disclosed in the foregoingdescription, it will be understood that variousmodifications within thespirit of the invention may occur to those skilled in the art. fore, itis intended that no limitations be placed on the invention except asdefined by the scope of the appended tion exposed to fluid from saidpumping space, whereby to collect particles ofthe fluorescent materialthereon in the There- (,1, event of leakage of the driving fluid intosaid pumping space, a source of exciting radiation, means to irradiatesaid face from said source, and photo-sensitive means mounted to receivefluorescent radiation from the particles of fluorescent materialcollecting on said face.

2. In combination, a fluid operated device of the type 7 comprising achamber, a flexible diaphragm mounted in said chamber and defining adriving fluid space on one side thereof and a pumping space on the othersidethereof, a driving fluid containing fluorescent material in saiddriving fluid space, a sampling chamber communicatively connected tosaid pumping space, a collection plate mounted obliquely in saidsampling chamber and having a substantially non-reflective face orientedso as to be exposedto fluid from said pumpingspace, whereby to collectparticles of the fluorescent material thereon in the event of leakage ofthe driving fluid into said pumping space, a source of excitingradiation, means to irradiate said face from said source, andphoto-sensitive means mounted to receive fluorescent radiation from theparticles of fluorescent material collecting on said face.

3. In combination, a fluid operated device of the type comprising achamber, a flexible diaphragm mounted in said chamber and defining adriving fluid space on one side thereof and a pumping space on the otherside thereof, a driving fluid containing fluorescent material in saiddriving fluid space, a sampling chamber, means to pass fluid from saidpumping space through said sampling chamber, a colleetionmember mountedin said sampling chamber and having a substantially non-reflectivecollection surface oriented obliquely in said chamber so as to beexposed to fluid passing through said sampling chamber, a source ofexciting radiation, means to irradiate said collection surface from saidsource, and photo-sensitive means mounted to receive fluorescentradiation from particles of fluorescent material deposited on saidcollection surface.

4. In a leak detector, a housing, a gas inlet conduit connected to oneend of the housing, a gas outlet conduit connected to the opposite endof the housing at a location offset from the gas inlet conduit, wherebyto pass gas through said housing, a collectionmember in said housinghaving a substantially non-reflective surface oriented obliquely so asto be exposed to the gas passing through said housing, whereby tocollect particles of fluorescent material carried by the gas, a sourceof exciting radiation, means to irradiate said surface from said source,and photo-sensitive means mounted directly opposite. said surface toreceive fluorescent radiation from particles of fluorescent materialdeposited on said surface.

5. The structure of claim 4, and wherein said collection membercomprises a plate obliquely arranged relative to the direction of gasflow through saidhousing.

6. The structure of claim 5, and wherein said irradiation means islocated so as to direct radiation onto said plate at an acute anglethereto and said photo-sensitive means is located to receive fluorescentradiation travelling in a direction substantially perpendicular to saidplate.

7. The structure of claim 4, and first filter means interposed betweensaid source and said surface limiting the exciting radiation to a firstpredetermined wavelength range, and second filter means interposedbetween said surface and said photo-sensitive means limiting thefluorescent radiation reaching said photo-sensitive means to V a secondpredetermined wavelength range.

driving fluid space, and fluid inlet and discharge conduit meansconnected to said pumping space, a leak detection chamber, conduit meansconnecting opposite ends of said leak detection chamber to spacedportions of said discharge conduit means, a collection member mounted insaid leak detection chamber and having an oblique substantiallynon-reflective face oriented in a position to receive leakage drivingfluid flowing through said leak detection chamber, a source of excitingradiation mounted to irradiate said face, and photo-sensitive meansmounted directly opposite said face to receive fluorescent radiationfrom particles of fluorescent material collecting on said face.

10. The structure of claim 9, and valve means in said means responsiveto the reception of fluorescent radiation by said photo-sensitive means.

References Cited by the Examiner UNITED STATES PATENTS 2,263,108 11/41Stuart 25071 2,593,313 4/52 Kamm 73-17 2,666,148 1/54 Arvintz 2502182,741,544 4/56 Chaikin 250-71 2,943,635 7/60 Greer 10344 3,061,723 10/62Kapff 250-71 LAURENCE V. EFNER,'Primary Examiner.

fluid inlet conduit means, and means to close said valve 15 ISAACLISANN, Examiner.

1. IN COMBINATION, A FLUID OPERATED DEVICE OF THE TYPE COMPRISING ACHAMBER, A FLEXIBLE DIAPHRAGM MOUNTED IN SAID CHAMBER AND DEFINING ADRIVING FLUID SPACE ON ONE SIDE THEREOF AND A PUMPING SPACE ON THE OTHERSIDE THEREOF, A DRIVING FLUID CONTAINING FLUORESCENT MATERIAL IN SAIDDRIVING FLUID SPACE, A SAMPLING CHAMBER COMMUNICATIVELY CONNECTED TOSAID PUMPING SPACE, A COLLECTION PLATE MOUNTED OBLIQUELY IN SAIDSAMPLING CHAMBER AND HAVING A SUBSTANTIALLY NON-RELFECTIVE FACE LOCATEDIN A POSITION EXPOSED TO FLUID FROM SAID PUMPING SPACE, WHEREBY TOCOLLECT PARTICLES OF THE FLUORESCENT MATERIAL THEREON IN THE EVENT OFLEAKAGE OF THE DRIVING FLUID INTO SAID PUMPING SPACE, A SOURCE OFEXCITING RADIATION, MEANS TO IRRADIATE SAID FACE FROM SAID SOURCE, ANDPHOTO-SENSITIVE MEANS